In addition to monitoring and summarizing the use of pesticides and other restricted chemicals as required under the California Agricultural Code, the collection of Use Reports by the California Department of Agriculture has facilitated the establishment of a data bank. This data bank is the source of detailed information, hitherto not available, on when, where, and how the chemicals were applied throughout the state over an extended period of time (five years to date). It is now possible to prepare graphs showing trends and changes in pesticide use, and to estimate the pesticide load for simulation modelling of dissipation and decomposition of selected compounds. In conjunction with the mapping program, the information in the data bank has been used to graphically depict areas of heavy application. Therefore, suitable areas for field monitoring of pesticides can be selected for air and soil sampling studies. The data balnk has also been used as an information source by various state and federal agencies, including the State Department of Water Resources, Environmental Protection Agency, Monterey Basin Monitoring Project, and several departments of the university.

The Project receives major support under National Science Foundation Grant BMS-74–11783. Robert Cooper (deceased), Urista Black, Steve Hartman, Haji M. Jameel and Patricia Horrigan have also assisted in the verification and programming procedures. The authors express their appreciation to C. E. Erickson and Associates, Oakland, California, for permission to use their maps as an: aid in the computer-produced map of Fresno County.